1. Field of the Invention
Embodiments of the present invention relate to the makeup of tubular strings at the surface of a well. More particularly, the invention relates to making up strings and running the strings into the well along with a control line or signal transmission line. More particularly still, the invention relates to methods and apparatus for facilitating the clamping of a control line or signal transmission line to a tubular string prior to lowering the string, clamp, and such line into the well.
Embodiments of the present invention also relate to methods and apparatus for preventing damage to the control line while running tubulars.
2. Description of the Related Art
Strings of pipe are typically run into a wellbore at various times during the formation and completion of a well. A wellbore is formed for example, by running a bit on the end of the tubular string of drill pipe. Later, larger diameter pipe is run into the wellbore and cemented therein to line the well and isolate certain parts of the wellbore from other parts. Smaller diameter tubular strings are then run through the lined wellbore either to form a new length of wellbore therebelow, to carry tools in the well, or to serve as a conduit for hydrocarbons gathered from the well during production.
As stated above, tools and other devices are routinely run into the wellbore on tubular strings for remote operation or communication. Some of these are operated mechanically by causing one part to move relative to another. Others are operated using natural forces like differentials between downhole pressure and atmospheric pressure. Others are operated hydraulically by adding pressure to a column of fluid in the tubular above the tool. Still others need a control line to provide either a signal, power, or both in order to operate the device or to serve as a conduit for communications between the device and the surface of the well. Control lines (also known as umbilical cords) can provide electrical, hydraulic, or fiber optic means of signal transmission, control and power.
Because the interior of a tubular string must be kept clear for fluids and other devices, control lines are often run into the well along an outer surface of the tubular string. For example, a tubular string may be formed at the surface of a well and, as it is inserted into the wellbore, a control line may be inserted into the wellbore adjacent the tubular string. The control line is typically provided from a reel or spool somewhere near the surface of the well and extends along the string to some component disposed in the string. Because of the harsh conditions and non-uniform surfaces in the wellbore, control lines are typically fixed to a tubular string along their length to keep the line and the tubular string together and prevent the control line from being damaged or pulled away from the tubular string during its trip into the well.
Control lines are typically attached to the tubular strings using clamps placed at predetermined intervals along the tubular string by an operator. Because various pieces of equipment at and above well center are necessary to build a tubular string and the control line is being fed from a remotely located reel, getting the control line close enough to the tubular string to successfully clamp it prior to entering the wellbore is a challenge. In one prior art solution, a separate device with an extendable member is used to urge the control line towards the tubular string as it comes off the reel. Such a device is typically fixed to the derrick structure at the approximate height of intended engagement with a tubular traversing the well center, the device being fixed at a significant distance from the well center. The device is telescopically moved toward and away from well center when operative and inoperative respectively. The device must necessarily span a fair distance as it telescopes from its out of the way mounting location to well center. Because of that the control line-engaging portion of the device is difficult to locate precisely at well center. The result is often a misalignment between the continuous control line and the tubular string making it necessary for an operator to manhandle the control line to a position adjacent the tubular before it can be clamped.
Another challenge to managing the control lines is the accidental closing of the slips around the control lines. Typically, while the control line is being clamped to the tubular string, the slips are open to allow the string and the newly clamped control line to be lowered into the wellbore. When the control line is near the tubular string, it is exposed to potential damage by the slips. Thus, if the slips are prematurely closed, the slips will cause damage to the control line.
There is a need therefore for an apparatus which facilitates the clamping of control line to a tubular string at the surface of a well. There is additionally a need for an apparatus which will help ensure that a control line is parallel to the center line of a tubular string as the control line and the string come together for clamping. There is also a need for an apparatus which will prevent the closing of the slips when the control line is near the tubular string.